Structure, in the form of "hiding places", can increase forage population. Some forage (fatheads come to mind) will be eaten to extinction without weeds or cover of some kind. Too much cover can support millions of insects, mollusks, and fish fry, most of which are normally eaten. That will arguably make the sport fish population a little skinnier. So,,, structure can change the *size* and *type* of critters, but doesn't have that great of an effect on the ultimate carrying capacity.
I think an ideal amount of cover promotes diversity without any 1 species starving or over-populating. I think diversity will help you maximize biomass with fewer problems than you have with a less diversified population.
